A conventional electrophotographic laser printer or an inkjet printer is capable of printing in a save mode so as to suppress consumption of printing materials such as toner or ink.
According to one of methods used in the save mode, printing of each respective dot is thinned out. Another method is used in the save mode, in which a save-mode dither matrix, instead of a normal-mode dither matrix, is used to binarize data. Each dot in the save-mode dither matrix is assigned with a value that is larger than a threshold value assigned to each dot in the normal-mode dither matrix. Thus, a gradation number is reduced in the save mode in comparison with a normal mode and thereby reduces the density.
Any conventional method used in the save mode has a problem that the visibility of characters is reduced. For example, thinning out each respective dot makes it difficult to discern small letters. Also, reducing the gradation number makes it difficult to make out variations in light and shade, making it difficult to see characters that have been set to a faint color.